Hooper Ian R, Sambles J R
School of Physics, University of Exeter, Exeter, Devon, UK.
Opt Express. 2008 Oct 27;16(22):17249-57. doi: 10.1364/oe.16.017258.
As interest in plasmonics grows the optical properties of thin metal films becomes increasingly significant. Here we explore the transmissivity of thin metal films at normal incidence, from the ultraviolet to microwaves, and show how, contrary to simplistic treatments, the microwave transmissivity may be much less than the optical transmissivity for films which are well below the skin depth in thickness. This arises because the film is acting as a zero order Fabry-Perot with very high reflectivity at each interface. The skin depth then becomes irrelevant for thin metal films at microwave frequencies. We also note in passing that the expected exponential dependence on thickness at higher thicknesses has an asymptotic limit at zero thickness which may be as high as four times the input intensity.
随着对等离激元学的兴趣不断增长，薄金属膜的光学性质变得越来越重要。在这里，我们研究了薄金属膜在垂直入射时从紫外线到微波波段的透射率，并表明，与简单的处理方法不同，对于厚度远低于趋肤深度的薄膜，其微波透射率可能远低于光学透射率。这是因为该薄膜起着零阶法布里 - 珀罗干涉仪的作用，在每个界面处具有非常高的反射率。因此，趋肤深度对于微波频率下的薄金属膜来说变得无关紧要。我们顺便还注意到，在较高厚度时预期的对厚度的指数依赖性在零厚度处有一个渐近极限，该极限可能高达输入强度的四倍。
